Method for applying glue to a surface of pieces of footwear and device that carries out this method

Abstract: A method for applying glue to the upper surface of soles for footwear consists of the following steps: transferring a sole to a first station (S₁) with the upper surface turned upward; picking up the outline of the sole; transferring the sole from the first station (S₁) to a second station (S₂), keeping the sole orientation unvaried; applying jet (26) of glue (27) directed to the upper surface of the sole along a path P that can be adjusted and that follows the border (30a) of the sole. In a different embodiment, glue is also applied to the surface of the upper that is intended for attaching of the sole.

Description: The present invention relates to manufacturing of footwear, in particular footwear in which glue, sometimes integrated with suitable seams, is used in order to fix the sole to the upper. At present, the glue is applied to the upper manually (a procedure that is obsolete because of the high cost of manpower) or automatically, that does not cause particular problems, since the part of upper to which glue is to be applied, is quite regular, without indentations or recesses. As far as sole is concerned, in some manufacturing processes, glue is not applied to the surface to be attached to the upper. In other manufacturing processes, glue is manually applied to this surface, more precisely, along a closed loop path close to the border of the sole, so as to match the corresponding portion of the upper. This way of proceeding has been often used up till now, in spite of high expense due to manpower cost, and health risk for the operators due to previous treatment of the surface to be glued with a halogenated substance. Some manufacturers have tried to automatically apply glue to the sole, using a brush that touches the upper surface of the sole; the relative motion between the sole and the brush makes this latter follow a closed loop path. It is known that the upper surface of the sole features lightening recesses and/or stiffening ridges. It is also known that it is difficult to grip, clamp, and handle the sole because of its flexibility and particular shape; e.g. sucking cups cannot be used due to the sole irregularities, and possible mechanical gripping and clamping means would bend the sole changing its space position. Consequently, the means used to apply the glue (i.e. the brush) touches one or more of the lightening recesses, or strikes one or more of the stiffening ridges; in both cases drops of glue can remain in the recess or on the ridge, thus causing all the problems well known to the field experts. As it has already been mentioned, the surface of the sole on which the glue is to be applied, is previously treated with a halogenated substance. This is performed by a suitable apparatus, at the outlet of which the soles are stored or directed, by known means, to a room, where the glue is applied in the previously described way. This procedure needs long processing time and special operative rooms, and consequently the production cost of the footwear is negatively affected. Publication EP-A-0.512.773 discloses an apparatus for roughing and subsequently applying adhesive to selected portions of a shoe upper, e.g. marginal portions of the bottom of a lasted shoe, has a camera (C) by which the roughed region is scanned and, from such scanning, the extent and also degree of rough are determined and stored as digitised information. From this information the acceptability of the roughing operation is determined, by comparison with a stored model, and then a pre-established path along which adhesive is to be applied can be corrected to ensure that adhesive is applied only to the roughed region. The apparatus disclosed in the EP-A-0.512.773 does not detect the outline of the shoe. The camera scans a region which is established in accordance with a pre-stored model and checks whether the roughing operation has been correctly performed in this region. It is well known that a lasted shoe, in particular an upper shoe, does not offer a flat surface but rather curved surface. Therefore, since the region do be glued is located along a curved part of the upper, which part is not necessarily the larger one, considering a vertical projection of the shoe, in such a case the camera does not picks up the outline of the shoe, but rather a strip of the vertical projection thereof, and this strip does not extend along the outline but rather a bit moved inward. It results that the path of the glue applying device does not depend on the actual outline of the shoe upper, but on the pre-established path of the roughed region, The scanning device has the sole purpose to check the quality of the roughing and, possibly, to define small adjustments in the path of the glue application device when the roughed region is somehow larger or narrower due to irregularities of the leather. The object of the present invention is to propose a method for applying glue along an adjustable and variable path which extends in a closed loop on the upper face of the sole, close to the border thereof, the whole procedure being carried out without any contact between the sole and the means used for applying the glue and with a free positioning of the sole onto a support. Another object of the invention is to propose a method according to which the above mentioned operation is performed correctly no matter of the orientation of the sole. Yet another object of the invention is to propose a method that fulfils all the aforementioned objects and furthermore, allows to apply the glue to the sole while this is freely resting on a suitable support. A further object of the invention is to propose an apparatus to carry out the proposed method. Yet a further object of the invention is to propose an apparatus that applies glue also to the upper for the intended sole, on the basis of the outline picked-up from the sole. Yet a further object of the invention is to propose an apparatus that applies glue also to the upper for the intended sole. The above mentioned objects are obtained in accordance with the contents of the claims. The characteristic features of the present invention are pointed out in the following with reference to the accompanying drawings, in which: Figure 1 shows a schematic plan view of the apparatus comprising a device carrying out the method being the subject of the present invention; Figures 2a, 2b show a sectional view taken along the line II-II of the apparatus in two different operating states; Figure 3, shows a sectional view taken along the line III-III of the Figure 1; Figure 4 shows an enlarged sectional view taken along the line IV-IV of Figure 3; Figure 5 shows a sectional view taken along the line V-V of Figure 4. Figure 6 shows a different embodiment of the device that carries out the present invention; Figure 7 shows a plan view of the device shown in Figure 6; Figures 8 and 9 correspond to Figures 4 and 5, but they refer to an upper instead of a sole. With reference to the above Figures, reference numeral 1 indicates a first conveyor including a series of wires 2 set side by side and trained around respective rollers, namely a fore roller 3 and a rear roller 4, so as to form a closed loop. The rollers 3, 4, one of which is driven in a known way by means which are not illustrated, feature suitable raceways, not shown in detail, aimed at receiving the wires. Between the raceways of the rear roller 4 there are made grooves 5 (Figures 2a, 2b) aimed at receiving respective prongs 6 of a comb-like lift-conveyor 7 located in a lowered position. There is also a second conveyor 9, similar to the conveyor 1. The rear roller 8 of the second conveyor and the roller 4 of the first one, are coaxial. Also the second conveyor 9 includes wires 10 (which are transparent for the reasons explained hereinafter) and a fore roller 11; grooves made in the said rear roller 8 are indicated with 12. The lift-conveyor 7 is moved by known means, not illustrated, between adjacent stations 50, 100, 150, with the intermediate station 100 centred with respect to the rear roller 4 and the rear roller 8. In each extreme station 50, 150, the lift-conveyor is moved between a lowered position A 1 , in which the prongs 6 enter the grooves 5, 12 of the rollers 4, 8, and a raised position A 2 that is kept while passing through and dwelling in the intermediate station 100. A device 13 for treating the soles with halogenated substance, is situated in the intermediate station 100, over the lift-conveyor 7. A transparent supporting plate 16a is situated at the top of a box-like element 16 that is positioned under the end of the upper run 9a of the conveyor 9. A light source, that is not shown, is placed inside the box-like element 16, and the light beam coming from the plate 16a is not weakened or troubled by the overlying wires 10, which are made, as already mentioned, of material transparent to the light radiation emitted by the source. A video camera 17, connected with a monitor 18, is situated over the box-like element 16 and the upper run 9a of the conveyor 9. Signals issued by the camera 17 are sent to a processing unit that works according to a programme and that is interlocked with a control panel 19 (Figure 1). The camera 17, the box-like element 16 and the portion of the upper run 9a situated therebetween, form a pick up station S 1 , or first station. Right after the second conveyor 9, there is a third conveyor 20, also including wires as the other ones, and the rear roller of the third conveyor is also the fore roller 11 of the conveyor 9. Over the upper run 20a of the conveyor 20, there is a spray gun 25 designed to eject a jet 26 of a suitable glue 27 (Figure 5). The gun 25 is carried by a longitudinal bar 28, that is moved transversally by known means, not shown, controlled by the processing unit. The spray gun is moved along the bar by other known means, not shown, also controlled by the same processing unit, which furthermore activates and deactivates the spray gun. Consequently, the nozzle 25a of the gun 25 is brought in a horizontal plane along a linear path of any kind, in particular in a closed loop. The upper run 20a of the conveyor 20 and the room occupied by the gun 25, form a second station S 2 , or glue applying station. Between the above mentioned stations, there is a shutter 29, that moves vertically (Figure 3) between a raised position, in which the soles pass freely from the first to the second station, and a lowered position, in which the first station is protected against possible glue spreading from the second station. The operation of the above described apparatus will be explained in detail in the following, with particular reference to the means that carry out the proposed method. The soles 30 are placed, in any orientation, on the first conveyor 1 with the upper surface 31, that is the surfaces that is intended for attaching to the sole, turned upward. In the extreme station 50, the lift-conveyor 7 is in the lowered position A 1 . When a sensor 32 detects a sole 30 that has reached a position thereunder, the conveyor 1 is stopped and the lift-conveyor 7 is activated (see Figures 2a, 2b). The lift-conveyor raises (in the direction F) from the lowered position A 1 to the raised position A 2 , with the sole 30 carried by the prongs 6 (Figure 2). At this moment, the lift-conveyor 7, while keeping in the raised position, translates (in the direction B) toward the other extreme station 150, passing through the station 100, where the upper surface 31 of the sole 30 undergoes a treatment by a jet H of known halogenated substances (Figure 2b). In the extreme station 150, the lift-conveyor is lowered until the prongs 6 are inserted in the grooves 12 of the roller 8, thus allowing the second conveyor 9 to bring the sole 30, already treated with halogenated substances, toward the first station S 1 . Obviously, the lift-conveyor 7 is raised, translated and lowered in order to take over a subsequent sole from the conveyor 1. The upper run 9a of the second conveyor 9 is long enough so as to allow the solvents, used during the treatment with the halogenated substances, to evaporate completely, before reaching the station S 1 . When the sole 30 is in the station S 1 , the conveyor 9 is stopped, thus permitting to perfectly pick up the outline 30a of the sole 30 by means of the camera 17. Also the orientation of the sole 30 with respect to the horizontal plane defined by the upper run 9a of the conveyor 9 is detected. The image picked up is shown on the monitor 18. The electric signals obtained by the image picked up are transmitted to the processing unit. The two conveyors 9, 20 are operated after the raising of the shutter 29, and the sole 30 is transferred to the second station S 2 , in which it remains for a predetermined time. It is to be pointed out that the sole remains in the same orientation, i.e. the orientation of the sole in the station S 2 is the same as in the station S 1 . In the station S 2 the gun 25 and the means provided to control it in two orthogonal directions, are activated, while the shutter 29 lowers in order to protect the station S 1 from spreading of glue. The nozzle 25a of the gun is made to move, in a horizontal plane, along a closed loop path, that is calculated for each sole and that follows the outline 30a of that sole. It is to be pointed out, that the jet 26 is preferably centred with respect to the axis of the nozzle 25a, and this allows to direct precisely the jet close to the border of the sole so as to define a path P that usually is like a closed loop. The operation can be better understood with reference to Figure 4, where a portion 40 of the glue strip 45 is illustrated, while the part not glued yet is indicated with 41 (sketched line). The distance X between the strip 45 and the outline 30a of the sole is calculated by a predetermined programme, but its length must prevent recesses 30b (Figure 5) or stiffening ridges, made on the surface 31, from being touched by the jet 26; this distance can be kept constant or varied according to the sole shape. The path P is like a closed loop but it can also be open or criss-crossed. The above described method has many advantages, among which the following: the soles are simply placed, oriented in any way, on suitable supports, in particular the wires of conveyors 9, 20; glue is applied without any contact between the surface 31 of the sole and the glue ejecting means (i.e. gun 25); the strip 45 of glue applied to the surface 31 extends along an adjustable path that is kept at a distance X from the outline 30a of the sole, which distance can be programmed, calculated and varied. It is to be pointed out that the above mentioned advantages are obtained independently from the shape and structure of the sole, as well as from orientation of the sole in the first station S 1 . The characteristic of the proposed method requires a very simple device 200 to be carried out, formed by the stations S 1 and S 2 , first and second and by means connected with the latter. In fact, there are not means for clamping and/or gripping and/or positioning the sole, since it is supported on the wires 10 of the conveyor 9 (station S 1 ) that cooperate, between the stations S 1 and S 2 , with the wires 22 of the conveyor 20, aimed at supporting the sole in the station S 2 . These conveyors 9, 20 cooperate, in the stations S 1 , S 2 , with the camera 17, with the associated box-like element 16, and with the gun 25 controlled by means that drive it along two orthogonal directions, the whole being interlocked with the processing unit. With reference to the accompanying figures, the conveyor 9 is fed with the soles coming from a station where they have been treated with halogenated substances, (that is the central station 100). This should not be considered as a limitation, since the conveyor 9 can be supplied in any way, e.g. with soles coming from a special store. The particular combination of the device 200 with the stations 50, 100, 150, and consequently with the means associated thereto, i.e. the lift-conveyor 7 and the conveyor 1, allows to provide a compact, versatile and functional apparatus that permits to treat the soles with halogenated substances and then, to apply glue thereto. A further advantage, besides the ones already mentioned, results from the fact that the conveyor 1 is fed with soles in any orientation, but with the upper surface turned upwards. The main advantage of the proposed method is that the glue is applied along a predetermined path P close to the outline 30a of the sole, without any contact between the gun and the surface 31. The above description provides breaks in the movement of the sole form station S 1 to station S 2 ; it is obvious that such breaks may be avoided. According to a different embodiment of the invention, carried out by the device shown in Figures 6 and 7, glue is also applied to the bottom 61 of the upper 60, in the same time, using the same method. However, while the sole 30 is a flat piece that can be easily placed on a support plane, the upper 60 is made of soft material, and therefore it must be set on a last 63, so as to have it well taut and easy to be supported. When the upper is set on the last, the outline 60a of the bottom cannot be picked up by means of a light beam directed upwards and a camera, because the lateral curvature 64 of the last, necessary to fit the shape of the upper, would be detected in certain zones, instead of the bottom outline. In fact, only the fore part 60b and the rear part 60c of the upper bottom profile are correctly picked up. Furthermore, the upper 60 mounted on the last 63 is rather higher than the sole 30. All the problems have been solved by providing at least two cabinets 70, 71 arranged side by side, in the first of which the outline 30a of the sole 30 is picked up and then glue is applied thereto, while in the second cabinet 71 glue is applied to the upper bottom 61 on the basis of the outline picked up from the sole. Obviously, the sole and the upper must be coupled, that is the upper must be the one that is to be adhered to that sole. In the first cabinet 70 two soles are treated while in the second one two uppers 60 undergo operation. Each sole 30 of the first cabinet is coupled with a respective upper of the second cabinet. The soles are placed, either manually or automatically, in the first cabinet 70, on a supporting light-transparent surface 73. Each sole is positioned so as to be located under one of two video cameras 117, which pick up the outlines of the respective soles as previously described. Two monitors 118 are connected to the cameras 117, respectively. Two light sources, not shown, are arranged inside two respective box-like elements 116 situated under the supporting surface 73, so as to emit a beam of light, upwardly directed, for each sole. When the outline 30a of the soles 30 is picked up, the spraying device 125 of the soles cabinet 70 is activated so as to spray glue along the border of both the soles, in the way previously described. In the same time, the soles profile images are transferred to a processing unit 100, to be processed as described in the following. In the second cabinet 71, the two uppers 60 are arranged basically like the sole 30, but turned upside down. The uppers 60 are mounted on respective lasts 63 which are removably fixed to a transparent supporting surface 74, e.g. by means of press fit couplings 75. Consequently, the bottom profile of each upper results reversed, in the transverse dimension, with respect to the respective sole outline. Also in the second cabinet there are two video cameras 217, each one directed toward a respective upper. The supporting surface 74 of the second cabinet 71 is set out at a level lower that the level of the supporting surface 73 of the first cabinet 70 for the soles. The difference in level can be adjusted to match the difference in height between the soles and the uppers mounted on the lasts. This differences in thus compensated. The cameras 217 of the second cabinet 71 pick up the outlines of the two uppers 60, with the help of two light sources 216 situated thereunder, and define the orientation assumed by each upper in the horizontal plane. Obviously, the uppers could be set out always in the same exact position, since the lasts are fixed to stationary points of the supporting plane, and accordingly the cameras could be omitted in the second cabinet, because the orientation of the uppers would be unvaried. In the example described herein, also two monitors 218 are provided and connected to the cameras 217 of the second cabinet 71, although they are not strictly necessary. The processing unit 100 reverses the electronic outline image of each sole 30, with respect to the transverse dimension only, thus obtaining a specular image that corresponds to the actual outline of the respective upper 60. The same electronic outline image is rotated and translated in the horizontal plane to make the rear and fore parts of it to match the fore and rear parts 60a,60b of the respective upper image. All these operations are performed in a very short time by the electronic processing unit 100. Finally, the spray gun 225 of the second cabinet is activated and a jet of glue 127 is sprayed on the bottom 61 of each upper 60 along a path Q that follows the outline 60a. The path Q is not altered by a wrong image of the upper profile due to the shape of the last 63, because it is obtained from the reversed outline of the corresponding sole 30. In the example described herein, two soles 30 and two uppers 60 can be disposed in the cabinets 70,71, but it is obvious that smaller cabinets will allow to treat only one sole and one upper at a time, whereas bigger cabinets will allow to treat three or more soles and uppers at the same time. Moreover, in the described example, two cameras are used in each cabinet, but only one camera could be provided for each cabinet, when a suitable programme is installed in the electronic processing unit. Finally, there is only one spray gun in each cabinet, but in order to expedite the process, two or more spray guns could be mounted in each cabinet, each one driven by respective means, according to the number of sole and uppers being treated.

Claims: Method for applying glue to a surface of pieces of footwear, characterised in that , it includes the following steps: placing a sole (30) on a first supporting means (9a), with the upper surface (31) of the said sole turned upward and with said sole freely resting on said supporting means (9a) with any possible orientation; transferring said sole (30), without changing its orientation, to a first station (S 1 ) where the outline is picked up, thus creating signals which are sent to a processing unit to determine a path extending close to the outline (30a) of the said sole (30); transferring said sole (30) to a second station (S 2 ), where a strip of glue is applied, along said path on the upper surface (31) of the said sole (30) by means of a glue applying means (25) moved in accordance with the outline of said sole previously picked up, said transferring between the said first and second stations being performed while keeping the same orientation of the said sole (30). Method according to claim 1, characterised in that in the said second station (S 2 ) the said sole (30) is halted for a time that can be previously set. Method according to claim 1, characterised in that also a shoe upper, is positioned on a second supporting means, mounted on a last and with the bottom turned upward, and a strip of glue is applied to the said bottom of the said upper by means of a second jet (26) of glue (27) directed to the said upper along a path (P) extending close to the outline (30a) of the said upper (60), the said path (P) being obtained by the reversed outline image of the corresponding sole (30) previously picked up. Method according to claim 3, characterised in that also the outline of the bottom of the said upper is picked up in order to locate in a horizontal plane a fore part and a rear part of it, the reverse outline image of the sole (30) being rotated and translated so that its fore and rear parts match the fore and rear part of the upper image. Method according to claim 4, characterised in that more than one sole (30) and one upper (P) are treated in the same time. Method according to claim 1, characterised in that the said path (P) is closed to form a loop. Device for applying glue to a surface of pieces of footwear, characterised in that , it includes: means for supporting a sole (30) freely resting on said supporting means with the upper surface (31) turned upward; means for transferring said sole (30) to a first station (S 1 ) without changing its orientation; pick up means (16,17,116,117,216,217) located in said first station (S 1 ) and designed to pick up the outline of the said sole (30), these picking up means being connected to an electronic processing unit (100) working in accordance with a predetermined programme; means for transferring said sole (30) to a second station (S 2 ); at least one sprayer means (25,125) located in said second station (S 2 ) for directing a jet (26) of glue (27) towards the upper surface (31) of the said sole (30), the said sprayer means (25,125) being moved in two perpendicular directions according to instructions delivered by the said processing unit (100) so that glue (27,127) is applied to the said sole (30) along a path (P) extending close to the outline (30a) of the same sole (30) previously picked up. Device according to claim 7, characterised in that the said means for supporting and transferring the said sole (30) include at least one conveyor (9,20) on which the said sole is placed to rest free and with any orientation, the said conveyor being located between said first and second stations (S 1 ,S 2 ). Device according to claim 8, characterised in that the said stations (S 1 ,S 2 ) first and second, are separated by a shielding shutter (29) movable vertically between a raised position, in which the soles (30) are allowed to pass thereunder while being transferred from the first station (S 1 ) to the second station (S 2 ), and a lowered position in which possible spreading of glue coming from the said second station (S 2 ) are prevented to go out therefrom. Device according to claim 8, characterised in that the said means for supporting and transferring said sole (30) include two conveyors (9,20) adjacent to each other, with the end of the first conveyor (9) being located in the said first station (S 1 ) and with the said second conveyor (20) being located, at least partially, in the said second station (S 2 ). Device according to claim 7, characterised in that the said means for supporting the said sole (30) include at least one conveyor (9) aimed at supporting the said sole (30), arranged in any orientation, transferred thereto by a lift-conveyor (7) that carries the said soles (30) through a station (13) where they are treated with a halogenated substance. Device according to claim 8, characterised in that the said conveyor (9) for supporting the said soles (30), arranged in any orientation, includes at least two rollers (8,11), namely a fore roller (11) and a rear roller (8), one of which is driven, with a series of transparent wires flanked to one another and trained around the said rollers (8,11), with the said lift-conveyor (7) being shaped like a comb and being moved between two extreme station (50,150) between which there is located the said station (100) for the treatment of the sole with halogenated substance, one station (150) of the said extreme stations being located over the said conveyor (9) for supporting the sole (30) while the other extreme station (50) is located over a fore roller (4) of a further conveyor (1) parallel to and made similar to the former one. Device according to claim 12, characterised in that the said lift-conveyor 7 when is located in the said extreme stations (50,150) is moved vertically between a lowered position (A1), in which prongs of the said lift-conveyor (7) are set free into respective grooves (5,12) made in the corresponding fore roller (4) of the said further conveyor (1) and in the rear roller (8) of the said supporting conveyor (9), and a raised position (A2) that is kept while the lift-conveyor (7) moves through the said station (100) for the treatment of the sole with halogenated substance. Device according to claim 7, characterised in that : the said means for supporting a sole (30) with the upper surface (31) turned upward, are located in a first cabinet (70) and there are further means for supporting a shoe upper located in a second cabinet (71); the said picking up means (116,117,216,217) are located both in the first cabinet (70), directed toward a sole (30), and in the second cabinet (71), directed toward an upper (60), the said upper (60) being mounted on a last (63) and overturned with the bottom (61) directed upward; the said sprayer means (125, 225) are also located both in the first cabinet (70) and in the said second cabinet (71); the said pick up means (116,117) and sprayer means (125) of the said first cabinet (70) are connected with the pick up means (216,217) and sprayer means (225) of the second cabinet (71) by a processing unit (100). Device according to claim 14, characterised in that the said means for supporting the said sole (30) and upper (60) include two transparent surfaces (73,74) positioned in the respective cabinets (70,71). Device according to claim 14, characterised in that the said last (63) on which the upper (60) is mounted, is supported by the respective transparent surface (74) of the said second cabinet (71) by means of press fit means (75). Device according to claim 14, characterised in that in the first cabinet (70) there are provided two pick up means (116,117) so that two soles (30) can be positioned therein, while in the second cabinet (71) there are provided two pick up means (216,217) so that two uppers (60) can be positioned therein. Device according to claim 9 and 14, characterised in that for each pick up means (16,17,116,117,216,217) there is a monitor (18,118,218) associated thereto.

Inventors: TALAMONTI FEDERICO, TALAMONTI SERGIO, TALAMONTI, FEDERICO, TALAMONTI, SERGIO
Applicants: TALAMONTI MACCHINE S N C FLLI, F.LLI TALAMONTI MACCHINE S.N.C.
Application year: 1994
Main classification: A43D25
IPC codes: A43D25, A43D119